World Congress of Malacology Antwerp ... - Unitas Malacologica

Invasive freshwater species Sinanodonta woodiana (Lea, 1834) (Bivalvia: Unionidae):
�a colonizer of the channels of Międzyodrze area (Western Pomerania Region, N-W Poland)
Domagała, Józef 1 , Łabęcka, Anna Maria 2 , Migdalska, Blandyna 3 , Pilecka-Rapacz, Małgorzata 4
1. University of Szczecin, Departament of General Zoology, Felczaka 3c, Szczecin 71-412, Poland,
Email: jozef.domagala@univ.szczecin.pl
2. University of Szczecin, Departament of General Zoology, Felczaka 3c, Szczecin 71-412, Poland,
Email: labecka@op.pl
3. Landscape Park Dolina Dolnej Odry, Armii Krajowej 36, 74-100 Gryfino, Poland,
Email: blankakontakt@poczta.onet.pl
4. University of Szczecin, Departament of General Zoology , Felczaka 3c, Szczecin 71-412, Poland,
Email: rapacz@univ.szczecin.pl
Sinanodonta woodiana (Lea, 1834) is an alien species in the fauna of Poland. It comes from the
catchment area of the rivers Amur and Yangtze. In Poland it was found in the early 1980s in the
system of heated lakes near Konin (Kujawy Lake District, C�Poland). It appeared there together with
the silver carp Hypophthalmichthys molitrix (Valenciennes, 1884) and big-heated carp Aristichthys
nobilis (Richardson, 1845) introduced from Hungary. In 2003 it was found in the release channel of
cooling water from the Dolna Odra power plant. In the years 2004-05 an inventory of the
Międzyodrze channels was made in order to determine the current range of occurrence of S.
woodiana in the Western Pomerania Region. The mussels were found at five localities below the
release of the cooling water. In total 20 empty shells joined by ligamentum and 16 live individuals
were collected. Histological analysis of the mussel gonads has shown the presence of ovulated
oocytes in females and developed spermatozoa in males. In the outer demibranch marsupia of
females the presence of glochidia was detected, which pointed to the readiness of the mussels for
reproduction. The channels of Międzyodrze are partly frozen in winter, which indicated the
adaptation abilities of this species to waters typical of temperate zone.
The relationship between age and shell length in freshwater pearl mussels (Margaritifera
margaritifera) from Sweden
Dunca, Elena 1 ; Söderberg, Håkan 2 ; Mutvei, Harry 1 ; Norgrann, Oskar 3
1. Swedish Museum of Natural History, Box 50007, 10405 Stockholm, Sweden,
Email: elena.dunca@nrm.se; harry.mutvei@nrm.se
2. Natur/kulturavdelningen, Länsstyrelsen Västernorrland, 871 86 Härnösand, Sweden,
Email: hakan.soderberg@y.lst.se
3. Miljöavdelningen, Länsstyrelsen Västernorrland, 871 86 Härnösand, Sweden,
Email: oskar.norrgrann@y.lst.se
The freshwater pearl mussel, Margaritifera margaritifera, is well known not only for its pearls but
also for reliable environmental archives within its shells. Unfortunately, this species is threatened by
extinction as many of populations through the Europe do not regenerate. Consequently, in most of the
European countries the freshwater pearl mussel is protected and there are general efforts to improve
the environmental conditions necessary for the regeneration of existing populations. Tools, such as
monitoring the population dynamics, improvement of the water quality (as example, liming) and
changes of the bottom sediment as well as studies on shell growth and structure are employed in
order to create sustainable conservation strategies.
The present paper presents general aspects of shell growth in freshwater pearl mussels from Swedish
populations. Unique shell material collected between 1984 and 2006 gave us opportunity to study the
shell growth of juvenile bivalves and to use it in order to estimate the eroded umbonal parts of old
shells. We have established the correlation between age and shell length in bivalves from 19 river
systems from South, Central and North Sweden. Consequently, a more precise age estimation of the
mussels by measuring the shell length is possible, which provide a better tool for monitoring of the
mussel populations. We did not find any North-South trend in the age distribution and shell length.
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